Unit 9 - Electrical Current

Unit 9 - Electrical Current

By S Harris

I know...

• ​how current, voltage, and resistance relate to one another.

Learning Target

i can...

• calculate current, voltage, or resistance when given a circuit scenario.​

Success Criteria

​

• this is the electric force per unit charge

  • it is radially outward from a positive

    charge

  • it is radially inward to a negative point

    charge

Electric Field

• this is the constant flow of electrons

​

Electric Current

REMEMBER​:

• conductors allow (let) electrons move easily​

• insulators do NOT let them flow easily​

​

Some text here about the topic of discussion

These have conductivity, but are not the best conductors.

• they are somewhere between an insulator and a conductor

  • these are essential components of most electronic circuits (example: silicon)​

Semiconductors

1. Voltage

2. Current

3. Resistance

3 Parts of and Electric Charge

this is the "push" that causes electrons to flow.

• it is electrical "pressure"

• units are Volts (V)​

• for electrons to flow their has to be a potential difference between 2 places

  • ​The charge will ​flow from high voltage to low voltage.

1.Voltage (V)

​There are 3 parts to an electric charge...

​There are 3 parts to an electric charge...

this is the measure of how many electrons per second are flowing through the wire

• ​units are amps (amperes; A)

• 2 types of current

  • AC (alternating current)

  • DC (direct current)​

2. Current (I)

this is an electrical current where the flow repeatedly changes direction

• voltage will go up and down as the current flows​

​​AC - alternating

​

this is an electrical current that flows only in one direction​

• source of voltage will be constant​

​​DC - direct

​

​There are 3 parts to an electric charge...

this is the tendency for a material to oppose (deny) the flow of electrons

• different materials have varying amounts of resistance

• units are Ohms​ (Ω)

• examples:

  • low R: gold, silver, copper, thick wires

  • hi​gh R: glass, plastics, wood, thin wires

3. Resistance (R)

Ohm's Law

​In a material, the current (I) is directly

proportional to the voltage (V) and

inversely proportional to the resistance (R).

​Equation:

​V = IR

PRACTICE PROBLEM

​

What is the current produced with a 9-volt battery through a resistance of 100 ohms?

​voltage

​current

​resistance

PRACTICE PROBLEM

​

What is the current produced with a 9-volt battery through a resistance of 100 ohms?

​9 V

100 Ω

I = ???

PRACTICE PROBLEM

​

What is the current produced with a 9-volt battery through a resistance of 100 ohms?

​9 V

100 Ω

I = ???

I = 9 V ÷ 100 Ω = 0.09 amps

Reading Graphs​

• What is the current produced when you have 2-volts?

• What is the resistance?

​Voltage (Volts)

Current (amps)

Reading Graphs​

• What is the current produced when you have 2-volts?

  • 0.4 amps

• What is the resistance?

​Voltage (Volts)

Current (amps)

Reading Graphs​

• What is the current produced when you have 2-volts?

  • 0.4 amps

• What is the resistance?

  • R = V/I

  • R = 2V ÷ 0.4 A = 5Ω

​Voltage (Volts)

Current (amps)

​2V

R= ?Ω

0.4 A